Quick release hook tape



P 30, 1969 H. EWHITACRE 3,469,289

QUICK RELEASE HOOK TAPE Filed Feb. 6, 1969 3 Sheets-Sheet 1 Horace E.Whifacre INVENTOR A TTOR/VE Y Sept. 30, 1969 H. E. WHITACRE 3,469,239

' QUICK RELEASE HOOK TAPE I Filed Feb. 6. 1969 :s Sheets-Sheet z 16 I6[6 I61 5 s l5 l4 2 la /7 l8 23 23 FIG. 4

Horace E. Whi/acre IN VE/V TOR ATTORNEY Sept. 30, 1969 H. E. WHITACREQUICK RELEASE HOOK TAPE Filed Feb. 6. 1969 5 Sheets-Sheet 5 r /& /6L/ /4/5 Horace E. Whit acre IN VE/V TOR A TT'OR/VEY United States Patent O3,469,289 QUICK RELEASE HOOK TAPE Horace E. Whitacre, Pasadena, Tex.,assignor to the United States of America as represented by theAdministrator of the National Aeronautics and Space Administration FiledFeb. 6, 1969, Ser. No. 797,056 Int. Cl. A44b 13/00 U.S. Cl. 24-20517 9Claims ABSTRACT OF THE DISCLOSURE Two relatively large and rigidsurfaces may be secured together with hook and loop fastener surfaces ina manner allowing relative rapidity and ease of separation by providingexpansible means distributed over the pile of one of the surfaces insuch a manner as to apply substantially uniformly distributed separationforces between the two mating pile surfaces when separation of therespective surfaces is desired.

ORIGIN OF THE INVENTION The invention described herein was made by anemployee of the United States Government and may be manufactured andused by or for the Government for governmentalpurposes without thepayment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION This invention relates to structuralfasteners of the quick releasing type. More specifically, this inventionrelates to a quick release mechanism for fasteners of the hook and looptype.

Hook and loop fasteners of the prior art have been described in US.Patents Nos. 2,717,473; 3,009,235, and 3,154,837. Hook and loopfasteners of this type have been manufactured by the American VelcroCorporation under the registered trademark of Velcro.

Hook and loop fasteners of the prior art comprise sheets or types ofco-operative fabric pile. Respective hook pile sheets and loop pilesheets are secured, contiguously, to the surfaces of two respectivestructures that are to be releasably fastened together. The individualpile elements of a hook sheet are a multiplicity of upstanding hookmembers. The elements of the loop pile may comprise a multiplicity ofupstanding loops or curled strands or both. These latter types of pilesurfaces are sometimes characterized as Astrakhan pile. When one hookand loop fastener pile surface is pressed against the pile of the othersurface, the hooks of the one engage the loops or eyes formed by thecurls of the other surface.

In order to disengage the two surfaces from each other, it is necessaryto bend the engaged hooks or curls until all the cooperatively engagedelements are released from each other. Each element is formed of aresilient material and requires a particular quantitiy of stressingforce to bend each hook sufiiciently to release it from a eo-operativeloop or curl. Although the disengaging force required to release eachindividual pair of hooks and loops is small, measured in units ofounces, yet when the cumulative effect of such small holding forcesmultiplied by the number of engaged pairs in a square inch of book andloop fastener pile is considered, the holding force may grow to themagnitude of 5 to 40 pounds per square inch depending on the particularmaterial from which the pile is fabricated. Typical of those materialsthat have been successfully used in the past are nylon, polyester, andstainless steel.

One of the more interesting facets of the hook and loop fastener is thefacility of exerting uniformly distributed securing forces over theentirety of the joined surface area without resorting to adhesives,fusing, or bonding agents. Accordingly, the two surfaces may berepeatedly joined and separated at will. However, if the joined area isof any appreciable size, the total force required for separation maybecome enormous. For this reason, the hook and loop fasteners has beenlimited in the past to structural surface pairs in which at least onemember of the pair is sufficiently flexible so as to allow the structureto be folded back on itself or peeled away from the other surfacemember. Examples of such uses are garment closures or the attachment offabric sheets to rigid surfaces.

SUMMARY OF THE INVENTION The present invention offers an apparatus bywhich large areas of mutually rigid surfaces may be secured together bythe hook and loop fastener technique and subsequently released by forcesdistributed broadly over the entire joined surface.

By providing rows of selectively expansible apparatus, such as pneumatictubes or strip cams, over one of the co-operative rigid surfaces securedby hook and loop fastener pile, the mutual engagement of the respectivehook and loop elements is unhindered when such apparatus is retracted.When the expansible apparatus is expanded, however, the rigid bases ofthe two surfaces are forced sufficiently far apart as to allow themutual release of the hook and loop elements comprising co-operatinghooks and Astrakhan pile elements each from the other.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects of the presentinvention may be more readily seen and understood by reference to thefollowing detailed description of the drawings wherein:

FIGURE 1 is an enlarged cross-sectional representation of a hook andloop fastener as it may be applied to rigid surfaces.

FIGURE 2 is a detailed illustration of the engagement relationshipbetween hook and loop components of a. hook and loop fastener.

FIGURE 3 is a perspective view of one embodiment of the invention.

FIGURE 4 is a cross-sectional view of the invention as applied to thehook and loop fastener pile surface and illustrates two possibleexpansion mechanisms in the collapsed condition.

FIGURE 5 shows a portion of the FIGURE 4 illustration with the expansionmechanisms in the expanded condition.

FIGURE 6 is a perspective view of another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIGURE 1 thereis shown a typical hook and loop fastener mechanism wherein a mat 1 offabric-like strands 2 having ends formed in the shape of hooks 3 issecured to a rigid surface 4 by means of a bonding agent 5. The oppositerigid surface 6 is provided with a dense pile mat 7 of loops or strands8 having the ends thereof curled in the shape of loops 9. The mat 7 mayalso be secured to the surface 6 by means of a bonding agent 10.

When pressed together, co-operative hook and loop elements 3 and 9,respectively, engage in the manner illustrated in FIG. 3 thereby firmlysecuring surfaces 4 and 6 together.

Since the material from which the hook and loop strands 2 and 8 arefabricated, i.g. nylon or stainless steel, for example, is of aresilient nature, it is necessary to overcome the preset shape of thestrand ends 3 and 9 by applying bending stress to separate the twosurfaces 4 and 6. In the case where one or both of the surfaces 4 or 6is of a flexible nature or is constituted of the mat per se, thisseparation may be accomplished by peeling the particular flexible mat sothat only the force necessary to overcome the disengaging stresses ofthose co-operative hook and loop elements along the line of peelingflexure need be applied. However, when hook and loop fasteners are usedto secure rigid surfaces together, as in the case to which the presentinvention is addressed, it is necessary to apply sufiicient separationforce to overcome the disengaging stresses of all engaged hook and loopelements over the entire area of the joined surfaces simultaneously.When such surfaces are reasonably large, this task becomes mechanicallydifficult.

One possible embodiment of applicants invention is illustrated in FIG. 3where there is shown a rigid surface 11 to which is attached, as bybonding means for example, groups 12 of curled end pile elements 13(FIGS. 4 and Retraction plate 14 having apertures 15 therethroughdistributed over the plane of said plate at intervals of spacingconsistent with the spacing of the pile groups 12 is positioned adjacentthe surface 11 with the pile elements 13 projecting through theapertures 15. Collars 16 may also be disposed around the groups 12 forpurposes to be seen hereafter.

The retraction mechanism may include strip earns 17 rotatably disposedabout journal shafts 18 mounted in bearing blocks 19. A parallelogramlinkage comprising crank links 20 pivotally secured at their ends to athrust link 21 ties the pivoted crank link 20 ends together forsimultaneous operation by an operating handle 22.

When the operating handle 22 is turned down adjacent the surface 11, allstrip earns 17 will rotate to the narrow profile position betweensurface 11 and retraction plate 14 shown in FIG. 4 thereby allowing thecurled loops 13 of pile groups 12 to project beyond the collars 16. Inthis position the loops 13 are adapted to receive hooks of aco-operative hook and loop fastener surface for attachment thereto.

To separate the two rigid surfaces, it is only necessary to rotate thehandle 22 to an upright position with respect to surface 14 therebyrotating strip cams 17 to the wide profile position between surface 11and plate 14 shown in FIG. 5. This action exerts an evenly distributeddisplacing force between surface 11 and plate 14 and draws the strandsof pile groups 12 into the confines of collars 16 to straighten out theloops 13 and consequently release all hooks engaged therewith.

In place of the rotating cam strips 17, expansible pneumatic tubes 23may be used to displace the plate 14 relative to surface 11 as alsoshown in FIGS. 4 and 5.

In another embodiment of the invention, illustrated in FIG. 6, the pilegroups may be arranged in continuous rows 24 separated by channelelements 25. Guide means (not illustrated) may be provided to assure theperpendicularly parallel displacement of channels 25 relative to surface11 when forced by the expansion of tubes under the force of pressurizedfluid such as air. Such expanded displacement of channels 25 draws thestrands of pile strips 24 between opposing faces of channel legs 26 todisengage the loops of said strips from co-operative hooks secured to anopposite surface.

Obviously, many modifications of the present invention are possible inlight of the above teachings. Although the described embodiments havebeen directed toward the loop or Astrakhan pile portion of the hook andloop fastener co-operatives, it should be understood that thedescription could have just as well been directed to the hook portion ofthe fastener. It should also be understood that the mutually rigidmating surfaces to which this invention is directed need not be flat orparallel planar surfaces, necessarily. It is sufficient that the matingsurfaces share a substantially common topographical contour. Dependingon the type of release mechanism employed, the

respective mating surfaces may be surfaces of straight line revolutionor warped. Accordingly, the invention may be practiced other than asspecifically described.

What is claimed is:

1. Releasable structural fastening means comprising:

a first rigid surface;

a second rigid surface topographically conforming with said first rigidsurface;

a multiplicity of resilient, thin strand, hook elements distributed oversaid first surface and secured thereto at one end;

Astrakhan pile means of resilient fabric secured to said second surface;and,

rows of expansible element, force exerting means secured to one of saidsurfaces to force said surfaces sufiiciently far apart to disengage saidhook elements from said pile means when the two are co-operativelyengaged.

2. Fastening means as described in claim 1 wherein:

said pile means comprises a multiplicity of curled strands having oneend secured to said surface, said strands being arranged insubstantially equally distributed groups over said second surface;

structural plate means having apertures distributed over the surfacethereof, each of said curled strand groups projecting through respectiveones of said apertures; and,

the rows of said force exerting means being disposed between the surfacesecured ends of said, strands and said plate means.

3. Fastening means as described in claim 1 wherein:

said hook elements are arranged in substantially equally distributedgroups over said first surface;

structural plate means having apertures distributed over the surfacethereof, each of said hook element groups projecting the hooks thereofthrough respective ones of said apertures; and,

the rows of said force exerting means being disposed between said firstsurface and said plate means.

4. Apparatus as described by claim 1 wherein groups of said hookelements are distributed over said surfaces in rows; and,

channel means disposed between respective rows of said hook elements,said expansible means being disposed between said surface and saidchannel means.

5. Apparatus as described by claim 4 wherein said expansible meanscomprise expansible tubular means adapted to be expanded by pressurizedfluid.

6. Apparatus as described by claim 4 wherein said expansible meanscomprise rotatable cam elements.

7. Apparatus as described by claim 1 wherein groups of said pile meansare distributed over said surface in rows; and,

channel means disposed between respective rows of said pile means, saidexpansible means being disposed between said surface and said channelmeans.

8. Apparatus as described by claim 7 wherein said expansible meanscomprise expansible tubular means adapted to be expanded by pressurizedfluid.

9. Apparatus as described by claim 7 wherein said expansible meanscomprise rotatable cam elements.

References Cited UNITED STATES PATENTS 3,320,649 5/1967 Naimer 24-204 XFOREIGN PATENTS 1,273,849 9/1961 France.

BERNARD A. GELAK, Primary Examiner US. Cl. X.R.

